U3: Oral Presentation C Friday, 11:30 am 12:00 pm C Gooseberry Falls Room

Extending Water Quality Monitoring: A Statewide Classification of Lake Water Clarity Using Landsat Imagery

Leif Olmanson, Marvin Bauer
University of Minnesota
Department of Forest Resources
Remote Sensing and Geospatial Analysis Laboratory
115 Green Hall
1530 Cleveland Avenue North
St. Paul, MN  55108

Patrick Brezonik
University of Minnesota
Water Resources Center
173 McNeal Hall
1985 Buford Avenue
St. Paul, MN  55108

Lakes are important environmental, economic and recreational resources in Minnesota. Monitoring and protecting lake water quality are major concerns for many local and state agencies. However, because of expense and time requirements for monitoring, it is effectively impossible to adequately monitor more than a small fraction of this large resource by conventional field methods. The use of satellite remote sensing is a cost-effective way to gather the information needed for regional water quality assessments. Based on a strong relationship between Landsat TM bands 1 and 3 and Secchi disk transparency we have developed an image processing and classification protocol that has been applied to more than 10,500 lakes in the state of Minnesota. This database has been used to assess spatial patterns in lake water quality based on surrounding land use and cover. As part of a NASA-sponsored Upper Great Lakes RESAC project, we are also applying this procedure to statewide assessments of the larger Upper Great Lakes region including the states of Michigan and Wisconsin. Results for the Minnesota statewide classification and the development of an Internet MapServer application that enables resource agencies and the public to access information on lakes will be described.